The invention concerns, in a general manner the control of aircraft jet engines and more specifically a particularly simple control device especially applicable to emergency control.
The conventional control of an aircraft jet engine comprises essentially a fuel pump powered by the engine and supplying a flow regulator, which is controlled as a function of various parameters so as to control the fuel flow to the passage section as necessary to supply the combustion chamber of the jet engine with a suitable flow of the fuel. Because the regulator is usually supplied at a variable pressure, accurate flow control may generally be obtained only by combining the regulator with a control valve which maintains the pressure across the regulator at a constant value, by means of regulating a by-pass flow at the inlet of said regulator. In advanced jet engines, controls must also regulate the cross section of the propulsive nozzle and the flow of afterburner fuel (if such is provided); certain parts of equipment additionally assure the supply of hydraulic power for the service appliances on the aircraft upon which the jet engine is mounted.
Such controls are highly complex. When jet engines comprise such controls, and particularly when the aircraft is equipped with a single jet engine, it is essential to provide the capability of overcoming possible control failures. Direct mechanical control of the flow regulator may be contemplated, in the manner of a control lever. However, such a direct regulator does not remedy, particularly, a rupture of the kinematic chain driving the fuel pump. It is thus desirable to provide complete emergency controls.